BENGALURU: Indian Institute of Science (IISc) researchers’ findings about how a mid-brain region is playing an active role in making humans pay attention is likely to help come up with new treatment schedules for conditions like Attention Deficit Hyperactivity Disorder (ADHD).Attention is widely associated with the outermost layer of the brain tissue called the cerebral cortex, which is also linked to awareness, thoughts, memory, language and consciousness. It is only recently that scientists began linking a mid-brain region called the Superior Colliculus (SC) with attention.
To demonstrate its role in attention, scientists had in recent years studied behaviour in monkeys during attention-demanding tasks. They observed that the monkeys were attentive when the SC was stimulated and distracted when this part of the brain was silenced.
But scientists were not sure how exactly SC promoted attention in humans. In the study, Devarajan Sridharan, Assistant Professor at IISc’s Centre for Neuroscience, and his PhD student Varsha Sreenivasan, conducted two sets of experiments in human participants, using non-invasive techniques. In one, they conducted a behaviour test on 22 participants, where they tracked changes in bias and sensitivity during attention-demanding tasks.
In the second experiment, they studied the anatomy of SC in 82 participants, including the 22 tested earlier. Using an imaging technique called diffusion Magnetic Resonance Imaging (dMRI), and a 3D modelling technique called tractography, they tracked white matter fibres in the brain connecting the SC with other regions, including the cortex.
When they compared the results of the two experiments, they found that SC connected with a part of the cerebral cortex called the parietal cortex, which has previously been associated with attention. They also show that the strength of SC-cortex connectivity can predict individuals’ bias, but not sensitivity.
The human brain is bombarded with information. It is through attention that it makes decisions efficiently. It processes relevant information and tunes out distractions. Understanding how attention works in the brain and how it controls behaviour can help scientists understand disorders such as ADHD, according to Sridharan.
The team plans to study the activity of SC using a different imaging technique called functional MRI (fMRI) that can identify increased blood oxygen levels in areas of the brain that are activated during tasks.
“Through fMRI, we will investigate if SC’s activity correlates with behavioural measures of sensitivity and bias. Our approach can help understand if SC-cortex connection asymmetries are predictive of certain kinds of attention disorders such as ADHD,” Varsha said.